I can't / don't want to use Windows. Is there a ".img" version of the installation image?

If you want to install TLXOS RPi, consider using Raspberry Pi Imager instead.  We have made it easy to image SD cards using this tool.

ThinLinX's own installation image is provided in Windows self-extractor format purely as a convenience for the  majority of customers who are more comfortable with Windows than Linux.  All it is is a 7-Zip container containing a very simple standalone disk imaging tool - Win32DiskImager - and the raw image file, and some scripting glue to automatically start up Win32DiskImager with the image loaded.

If you want to use some other imaging tool, you can use 7-Zip (https://www.7-zip.org/) to extract the raw image from the exe file.  Please note that we will assume that you know what you are doing with your alternative imaging tool, and will not answer any questions about failure to create a bootable device using an alternative imager (for example, if you choose to install using "dd", it's important that you use "conv=fsync" or "conv=fdatasync" to ensure that data is actually flushed to disk before the dd process exits).  One of the main reasons we chose Win32DiskImager is that it is almost impossible to get it wrong (unlike Rufus, Balena Etcher et al, which have extra knobs and buttons that can get you in trouble).

If you are using Linux, the appropriate 7-Zip package is probably named "p7zip" (e.g. apt-get/yum/dnf install p7zip).  Use a command like "7zr x tlxos_rpi-4.9.2.exe" (or, more surgically, "7zr x tlxos_rpi-4.9.2.exe rpi-4.9.2.img") to extract the image.

If you are using Mac OS, please note that GUI disk imaging tools for Mac OS will most likely either not support 7-Zip or refuse to treat an exe file as an archive.  Please install actual 7-Zip (p7zip) via Homebrew (or Fink, or MacPorts - take your pick, but most people wanting a decent open source toolset seem to prefer Homebrew). See https://brew.sh/ for install instructions; after bootstrapping brew you can just use "brew install p7zip" and then use a command like "7zr x tlxos_rpi-4.9.2.exe rpi-4.9.2.img".